>>53076201Misty's story and arc is different from Serena's. Serena had a obsession with him and left so she could "become a better woman for him". Her development would involve realizing she just needs to become a better woman, Ash doesn't and shouldn't be part of that.
Misty left because of herself and her sisters. It had nothing to do with him. She went to live her own life. And then, as time passes, she realizes this was not what she wanted. She wanted to journey around, just like Ash. And so, by pure coincidence, they end up meeting again. Misty didn't stalk or seek him out, they just happened to be at the same place at the same time as she went on her journey. She didn't try to improve so she could be a better woman for him, because she'd hate to admit she has feelings for the guy. But still, she does, and she comes to the understanding that, if she's gonna be traveling anyway... Why not join him? She's happier this way.
And not a single time does either of them try to change the way the other is.